// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/gpu/vaapi_video_encode_accelerator.h"

#include <string.h>

#include <memory>
#include <utility>

#include "base/bind.h"
#include "base/callback.h"
#include "base/macros.h"
#include "base/metrics/histogram.h"
#include "base/numerics/safe_conversions.h"
#include "base/single_thread_task_runner.h"
#include "base/threading/thread_task_runner_handle.h"
#include "media/base/bind_to_current_loop.h"
#include "media/gpu/h264_dpb.h"
#include "media/gpu/shared_memory_region.h"
#include "third_party/libva/va/va_enc_h264.h"

#define DVLOGF(level) DVLOG(level) << __func__ << "(): "

#define NOTIFY_ERROR(error, msg)                              \
    do {                                                      \
        SetState(kError);                                     \
        LOG(ERROR) << msg;                                    \
        LOG(ERROR) << "Calling NotifyError(" << error << ")"; \
        NotifyError(error);                                   \
    } while (0)

namespace media {

namespace {
    // Need 2 surfaces for each frame: one for input data and one for
    // reconstructed picture, which is later used for reference.
    const size_t kMinSurfacesToEncode = 2;

    // Subjectively chosen.
    const size_t kNumInputBuffers = 4;
    const size_t kMaxNumReferenceFrames = 4;

    // We need up to kMaxNumReferenceFrames surfaces for reference, plus one
    // for input and one for encode (which will be added to the set of reference
    // frames for subsequent frames). Actual execution of HW encode is done
    // in parallel, and we want to process more frames in the meantime.
    // To have kNumInputBuffers in flight, we need a full set of reference +
    // encode surfaces (i.e. kMaxNumReferenceFrames + kMinSurfacesToEncode), and
    // (kNumInputBuffers - 1) of kMinSurfacesToEncode for the remaining frames
    // in flight.
    const size_t kNumSurfaces = kMaxNumReferenceFrames + kMinSurfacesToEncode + kMinSurfacesToEncode * (kNumInputBuffers - 1);

    // An IDR every 2048 frames, an I frame every 256 and no B frames.
    // We choose IDR period to equal MaxFrameNum so it must be a power of 2.
    const int kIDRPeriod = 2048;
    const int kIPeriod = 256;
    const int kIPPeriod = 1;

    const int kDefaultFramerate = 30;

    // HRD parameters (ch. E.2.2 in spec).
    const int kBitRateScale = 0; // bit_rate_scale for SPS HRD parameters.
    const int kCPBSizeScale = 0; // cpb_size_scale for SPS HRD parameters.

    const int kDefaultQP = 26;
    // All Intel codecs can do at least 4.1.
    const int kDefaultLevelIDC = 41;
    const int kChromaFormatIDC = 1; // 4:2:0

    // Arbitrarily chosen bitrate window size for rate control, in ms.
    const int kCPBWindowSizeMs = 1500;

    // UMA errors that the VaapiVideoEncodeAccelerator class reports.
    enum VAVEAEncoderFailure {
        VAAPI_ERROR = 0,
        VAVEA_ENCODER_FAILURES_MAX,
    };
}

// Round |value| up to |alignment|, which must be a power of 2.
static inline size_t RoundUpToPowerOf2(size_t value, size_t alignment)
{
    // Check that |alignment| is a power of 2.
    DCHECK((alignment + (alignment - 1)) == (alignment | (alignment - 1)));
    return ((value + (alignment - 1)) & ~(alignment - 1));
}

static void ReportToUMA(VAVEAEncoderFailure failure)
{
    UMA_HISTOGRAM_ENUMERATION("Media.VAVEA.EncoderFailure", failure,
        VAVEA_ENCODER_FAILURES_MAX + 1);
}

struct VaapiVideoEncodeAccelerator::InputFrameRef {
    InputFrameRef(const scoped_refptr<VideoFrame>& frame, bool force_keyframe)
        : frame(frame)
        , force_keyframe(force_keyframe)
    {
    }
    const scoped_refptr<VideoFrame> frame;
    const bool force_keyframe;
};

struct VaapiVideoEncodeAccelerator::BitstreamBufferRef {
    BitstreamBufferRef(int32_t id, std::unique_ptr<SharedMemoryRegion> shm)
        : id(id)
        , shm(std::move(shm))
    {
    }
    const int32_t id;
    const std::unique_ptr<SharedMemoryRegion> shm;
};

VideoEncodeAccelerator::SupportedProfiles
VaapiVideoEncodeAccelerator::GetSupportedProfiles()
{
    return VaapiWrapper::GetSupportedEncodeProfiles();
}

static unsigned int Log2OfPowerOf2(unsigned int x)
{
    CHECK_GT(x, 0u);
    DCHECK_EQ(x & (x - 1), 0u);

    int log = 0;
    while (x > 1) {
        x >>= 1;
        ++log;
    }
    return log;
}

VaapiVideoEncodeAccelerator::VaapiVideoEncodeAccelerator()
    : profile_(VIDEO_CODEC_PROFILE_UNKNOWN)
    , mb_width_(0)
    , mb_height_(0)
    , output_buffer_byte_size_(0)
    , state_(kUninitialized)
    , frame_num_(0)
    , idr_pic_id_(0)
    , bitrate_(0)
    , framerate_(0)
    , cpb_size_(0)
    , encoding_parameters_changed_(false)
    , encoder_thread_("VAVEAEncoderThread")
    , child_task_runner_(base::ThreadTaskRunnerHandle::Get())
    , weak_this_ptr_factory_(this)
{
    DVLOGF(4);
    weak_this_ = weak_this_ptr_factory_.GetWeakPtr();

    max_ref_idx_l0_size_ = kMaxNumReferenceFrames;
    qp_ = kDefaultQP;
    idr_period_ = kIDRPeriod;
    i_period_ = kIPeriod;
    ip_period_ = kIPPeriod;
}

VaapiVideoEncodeAccelerator::~VaapiVideoEncodeAccelerator()
{
    DVLOGF(4);
    DCHECK(child_task_runner_->BelongsToCurrentThread());
    DCHECK(!encoder_thread_.IsRunning());
}

bool VaapiVideoEncodeAccelerator::Initialize(
    VideoPixelFormat format,
    const gfx::Size& input_visible_size,
    VideoCodecProfile output_profile,
    uint32_t initial_bitrate,
    Client* client)
{
    DCHECK(child_task_runner_->BelongsToCurrentThread());
    DCHECK(!encoder_thread_.IsRunning());
    DCHECK_EQ(state_, kUninitialized);

    DVLOGF(1) << "Initializing VAVEA, input_format: "
              << VideoPixelFormatToString(format)
              << ", input_visible_size: " << input_visible_size.ToString()
              << ", output_profile: " << GetProfileName(output_profile)
              << ", initial_bitrate: " << initial_bitrate;

    client_ptr_factory_.reset(new base::WeakPtrFactory<Client>(client));
    client_ = client_ptr_factory_->GetWeakPtr();

    const SupportedProfiles& profiles = GetSupportedProfiles();
    auto profile = find_if(profiles.begin(), profiles.end(),
        [output_profile](const SupportedProfile& profile) {
            return profile.profile == output_profile;
        });
    if (profile == profiles.end()) {
        DVLOGF(1) << "Unsupported output profile "
                  << GetProfileName(output_profile);
        return false;
    }
    if (input_visible_size.width() > profile->max_resolution.width() || input_visible_size.height() > profile->max_resolution.height()) {
        DVLOGF(1) << "Input size too big: " << input_visible_size.ToString()
                  << ", max supported size: " << profile->max_resolution.ToString();
        return false;
    }

    if (format != PIXEL_FORMAT_I420) {
        DVLOGF(1) << "Unsupported input format: "
                  << VideoPixelFormatToString(format);
        return false;
    }

    profile_ = output_profile;
    visible_size_ = input_visible_size;
    // 4:2:0 format has to be 2-aligned.
    DCHECK_EQ(visible_size_.width() % 2, 0);
    DCHECK_EQ(visible_size_.height() % 2, 0);
    coded_size_ = gfx::Size(RoundUpToPowerOf2(visible_size_.width(), 16),
        RoundUpToPowerOf2(visible_size_.height(), 16));
    mb_width_ = coded_size_.width() / 16;
    mb_height_ = coded_size_.height() / 16;
    output_buffer_byte_size_ = coded_size_.GetArea();

    UpdateRates(initial_bitrate, kDefaultFramerate);

    vaapi_wrapper_ = VaapiWrapper::CreateForVideoCodec(VaapiWrapper::kEncode, output_profile,
        base::Bind(&ReportToUMA, VAAPI_ERROR));
    if (!vaapi_wrapper_.get()) {
        DVLOGF(1) << "Failed initializing VAAPI for profile "
                  << GetProfileName(output_profile);
        return false;
    }

    if (!encoder_thread_.Start()) {
        LOG(ERROR) << "Failed to start encoder thread";
        return false;
    }
    encoder_thread_task_runner_ = encoder_thread_.task_runner();

    // Finish the remaining initialization on the encoder thread.
    encoder_thread_task_runner_->PostTask(
        FROM_HERE, base::Bind(&VaapiVideoEncodeAccelerator::InitializeTask, base::Unretained(this)));

    return true;
}

void VaapiVideoEncodeAccelerator::InitializeTask()
{
    DCHECK(encoder_thread_task_runner_->BelongsToCurrentThread());
    DCHECK_EQ(state_, kUninitialized);
    DVLOGF(4);

    va_surface_release_cb_ = BindToCurrentLoop(
        base::Bind(&VaapiVideoEncodeAccelerator::RecycleVASurfaceID,
            base::Unretained(this)));

    if (!vaapi_wrapper_->CreateSurfaces(VA_RT_FORMAT_YUV420, coded_size_,
            kNumSurfaces,
            &available_va_surface_ids_)) {
        NOTIFY_ERROR(kPlatformFailureError, "Failed creating VASurfaces");
        return;
    }

    UpdateSPS();
    GeneratePackedSPS();

    UpdatePPS();
    GeneratePackedPPS();

    child_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&Client::RequireBitstreamBuffers, client_, kNumInputBuffers,
            coded_size_, output_buffer_byte_size_));

    SetState(kEncoding);
}

void VaapiVideoEncodeAccelerator::RecycleVASurfaceID(
    VASurfaceID va_surface_id)
{
    DVLOGF(4) << "va_surface_id: " << va_surface_id;
    DCHECK(encoder_thread_task_runner_->BelongsToCurrentThread());

    available_va_surface_ids_.push_back(va_surface_id);
    EncodeFrameTask();
}

void VaapiVideoEncodeAccelerator::BeginFrame(bool force_keyframe)
{
    current_pic_ = new H264Picture();

    // If the current picture is an IDR picture, frame_num shall be equal to 0.
    if (force_keyframe)
        frame_num_ = 0;

    current_pic_->frame_num = frame_num_++;
    frame_num_ %= idr_period_;

    if (current_pic_->frame_num == 0) {
        current_pic_->idr = true;
        // H264 spec mandates idr_pic_id to differ between two consecutive IDRs.
        idr_pic_id_ ^= 1;
        ref_pic_list0_.clear();
    }

    if (current_pic_->frame_num % i_period_ == 0)
        current_pic_->type = H264SliceHeader::kISlice;
    else
        current_pic_->type = H264SliceHeader::kPSlice;

    if (current_pic_->type != H264SliceHeader::kBSlice)
        current_pic_->ref = true;

    current_pic_->pic_order_cnt = current_pic_->frame_num * 2;
    current_pic_->top_field_order_cnt = current_pic_->pic_order_cnt;
    current_pic_->pic_order_cnt_lsb = current_pic_->pic_order_cnt;

    current_encode_job_->keyframe = current_pic_->idr;

    DVLOGF(4) << "Starting a new frame, type: " << current_pic_->type
              << (force_keyframe ? " (forced keyframe)" : "")
              << " frame_num: " << current_pic_->frame_num
              << " POC: " << current_pic_->pic_order_cnt;
}

void VaapiVideoEncodeAccelerator::EndFrame()
{
    DCHECK(current_pic_);
    // Store the picture on the list of reference pictures and keep the list
    // below maximum size, dropping oldest references.
    if (current_pic_->ref)
        ref_pic_list0_.push_front(current_encode_job_->recon_surface);
    size_t max_num_ref_frames = base::checked_cast<size_t>(current_sps_.max_num_ref_frames);
    while (ref_pic_list0_.size() > max_num_ref_frames)
        ref_pic_list0_.pop_back();

    submitted_encode_jobs_.push(make_linked_ptr(current_encode_job_.release()));
}

static void InitVAPicture(VAPictureH264* va_pic)
{
    memset(va_pic, 0, sizeof(*va_pic));
    va_pic->picture_id = VA_INVALID_ID;
    va_pic->flags = VA_PICTURE_H264_INVALID;
}

bool VaapiVideoEncodeAccelerator::SubmitFrameParameters()
{
    DCHECK(current_pic_);
    VAEncSequenceParameterBufferH264 seq_param;
    memset(&seq_param, 0, sizeof(seq_param));

#define SPS_TO_SP(a) seq_param.a = current_sps_.a;
    SPS_TO_SP(seq_parameter_set_id);
    SPS_TO_SP(level_idc);

    seq_param.intra_period = i_period_;
    seq_param.intra_idr_period = idr_period_;
    seq_param.ip_period = ip_period_;
    seq_param.bits_per_second = bitrate_;

    SPS_TO_SP(max_num_ref_frames);
    seq_param.picture_width_in_mbs = mb_width_;
    seq_param.picture_height_in_mbs = mb_height_;

#define SPS_TO_SP_FS(a) seq_param.seq_fields.bits.a = current_sps_.a;
    SPS_TO_SP_FS(chroma_format_idc);
    SPS_TO_SP_FS(frame_mbs_only_flag);
    SPS_TO_SP_FS(log2_max_frame_num_minus4);
    SPS_TO_SP_FS(pic_order_cnt_type);
    SPS_TO_SP_FS(log2_max_pic_order_cnt_lsb_minus4);
#undef SPS_TO_SP_FS

    SPS_TO_SP(bit_depth_luma_minus8);
    SPS_TO_SP(bit_depth_chroma_minus8);

    SPS_TO_SP(frame_cropping_flag);
    if (current_sps_.frame_cropping_flag) {
        SPS_TO_SP(frame_crop_left_offset);
        SPS_TO_SP(frame_crop_right_offset);
        SPS_TO_SP(frame_crop_top_offset);
        SPS_TO_SP(frame_crop_bottom_offset);
    }

    SPS_TO_SP(vui_parameters_present_flag);
#define SPS_TO_SP_VF(a) seq_param.vui_fields.bits.a = current_sps_.a;
    SPS_TO_SP_VF(timing_info_present_flag);
#undef SPS_TO_SP_VF
    SPS_TO_SP(num_units_in_tick);
    SPS_TO_SP(time_scale);
#undef SPS_TO_SP

    if (!vaapi_wrapper_->SubmitBuffer(VAEncSequenceParameterBufferType,
            sizeof(seq_param), &seq_param))
        return false;

    VAEncPictureParameterBufferH264 pic_param;
    memset(&pic_param, 0, sizeof(pic_param));

    pic_param.CurrPic.picture_id = current_encode_job_->recon_surface->id();
    pic_param.CurrPic.TopFieldOrderCnt = current_pic_->top_field_order_cnt;
    pic_param.CurrPic.BottomFieldOrderCnt = current_pic_->bottom_field_order_cnt;
    pic_param.CurrPic.flags = 0;

    for (size_t i = 0; i < arraysize(pic_param.ReferenceFrames); ++i)
        InitVAPicture(&pic_param.ReferenceFrames[i]);

    DCHECK_LE(ref_pic_list0_.size(), arraysize(pic_param.ReferenceFrames));
    RefPicList::const_iterator iter = ref_pic_list0_.begin();
    for (size_t i = 0;
         i < arraysize(pic_param.ReferenceFrames) && iter != ref_pic_list0_.end();
         ++iter, ++i) {
        pic_param.ReferenceFrames[i].picture_id = (*iter)->id();
        pic_param.ReferenceFrames[i].flags = 0;
    }

    pic_param.coded_buf = current_encode_job_->coded_buffer;
    pic_param.pic_parameter_set_id = current_pps_.pic_parameter_set_id;
    pic_param.seq_parameter_set_id = current_pps_.seq_parameter_set_id;
    pic_param.frame_num = current_pic_->frame_num;
    pic_param.pic_init_qp = qp_;
    pic_param.num_ref_idx_l0_active_minus1 = max_ref_idx_l0_size_ - 1;
    pic_param.pic_fields.bits.idr_pic_flag = current_pic_->idr;
    pic_param.pic_fields.bits.reference_pic_flag = current_pic_->ref;
#define PPS_TO_PP_PF(a) pic_param.pic_fields.bits.a = current_pps_.a;
    PPS_TO_PP_PF(entropy_coding_mode_flag);
    PPS_TO_PP_PF(transform_8x8_mode_flag);
    PPS_TO_PP_PF(deblocking_filter_control_present_flag);
#undef PPS_TO_PP_PF

    if (!vaapi_wrapper_->SubmitBuffer(VAEncPictureParameterBufferType,
            sizeof(pic_param), &pic_param))
        return false;

    VAEncSliceParameterBufferH264 slice_param;
    memset(&slice_param, 0, sizeof(slice_param));

    slice_param.num_macroblocks = mb_width_ * mb_height_;
    slice_param.macroblock_info = VA_INVALID_ID;
    slice_param.slice_type = current_pic_->type;
    slice_param.pic_parameter_set_id = current_pps_.pic_parameter_set_id;
    slice_param.idr_pic_id = idr_pic_id_;
    slice_param.pic_order_cnt_lsb = current_pic_->pic_order_cnt_lsb;
    slice_param.num_ref_idx_active_override_flag = true;

    for (size_t i = 0; i < arraysize(slice_param.RefPicList0); ++i)
        InitVAPicture(&slice_param.RefPicList0[i]);

    for (size_t i = 0; i < arraysize(slice_param.RefPicList1); ++i)
        InitVAPicture(&slice_param.RefPicList1[i]);

    DCHECK_LE(ref_pic_list0_.size(), arraysize(slice_param.RefPicList0));
    iter = ref_pic_list0_.begin();
    for (size_t i = 0;
         i < arraysize(slice_param.RefPicList0) && iter != ref_pic_list0_.end();
         ++iter, ++i) {
        InitVAPicture(&slice_param.RefPicList0[i]);
        slice_param.RefPicList0[i].picture_id = (*iter)->id();
        slice_param.RefPicList0[i].flags = 0;
    }

    if (!vaapi_wrapper_->SubmitBuffer(VAEncSliceParameterBufferType,
            sizeof(slice_param), &slice_param))
        return false;

    VAEncMiscParameterRateControl rate_control_param;
    memset(&rate_control_param, 0, sizeof(rate_control_param));
    rate_control_param.bits_per_second = bitrate_;
    rate_control_param.target_percentage = 90;
    rate_control_param.window_size = kCPBWindowSizeMs;
    rate_control_param.initial_qp = qp_;
    rate_control_param.rc_flags.bits.disable_frame_skip = true;

    if (!vaapi_wrapper_->SubmitVAEncMiscParamBuffer(
            VAEncMiscParameterTypeRateControl, sizeof(rate_control_param),
            &rate_control_param))
        return false;

    VAEncMiscParameterFrameRate framerate_param;
    memset(&framerate_param, 0, sizeof(framerate_param));
    framerate_param.framerate = framerate_;
    if (!vaapi_wrapper_->SubmitVAEncMiscParamBuffer(
            VAEncMiscParameterTypeFrameRate, sizeof(framerate_param),
            &framerate_param))
        return false;

    VAEncMiscParameterHRD hrd_param;
    memset(&hrd_param, 0, sizeof(hrd_param));
    hrd_param.buffer_size = cpb_size_;
    hrd_param.initial_buffer_fullness = cpb_size_ / 2;
    if (!vaapi_wrapper_->SubmitVAEncMiscParamBuffer(
            VAEncMiscParameterTypeHRD, sizeof(hrd_param), &hrd_param))
        return false;

    return true;
}

bool VaapiVideoEncodeAccelerator::SubmitHeadersIfNeeded()
{
    DCHECK(current_pic_);
    if (current_pic_->type != H264SliceHeader::kISlice)
        return true;

    // Submit SPS.
    VAEncPackedHeaderParameterBuffer par_buffer;
    memset(&par_buffer, 0, sizeof(par_buffer));
    par_buffer.type = VAEncPackedHeaderSequence;
    par_buffer.bit_length = packed_sps_.BytesInBuffer() * 8;

    if (!vaapi_wrapper_->SubmitBuffer(VAEncPackedHeaderParameterBufferType,
            sizeof(par_buffer), &par_buffer))
        return false;

    if (!vaapi_wrapper_->SubmitBuffer(VAEncPackedHeaderDataBufferType,
            packed_sps_.BytesInBuffer(),
            packed_sps_.data()))
        return false;

    // Submit PPS.
    memset(&par_buffer, 0, sizeof(par_buffer));
    par_buffer.type = VAEncPackedHeaderPicture;
    par_buffer.bit_length = packed_pps_.BytesInBuffer() * 8;

    if (!vaapi_wrapper_->SubmitBuffer(VAEncPackedHeaderParameterBufferType,
            sizeof(par_buffer), &par_buffer))
        return false;

    if (!vaapi_wrapper_->SubmitBuffer(VAEncPackedHeaderDataBufferType,
            packed_pps_.BytesInBuffer(),
            packed_pps_.data()))
        return false;

    return true;
}

bool VaapiVideoEncodeAccelerator::ExecuteEncode()
{
    DCHECK(current_pic_);
    DVLOGF(3) << "Encoding frame_num: " << current_pic_->frame_num;
    return vaapi_wrapper_->ExecuteAndDestroyPendingBuffers(
        current_encode_job_->input_surface->id());
}

bool VaapiVideoEncodeAccelerator::UploadFrame(
    const scoped_refptr<VideoFrame>& frame)
{
    return vaapi_wrapper_->UploadVideoFrameToSurface(
        frame, current_encode_job_->input_surface->id());
}

void VaapiVideoEncodeAccelerator::TryToReturnBitstreamBuffer()
{
    DCHECK(encoder_thread_task_runner_->BelongsToCurrentThread());

    if (state_ != kEncoding)
        return;

    if (submitted_encode_jobs_.empty() || available_bitstream_buffers_.empty())
        return;

    linked_ptr<BitstreamBufferRef> buffer = available_bitstream_buffers_.front();
    available_bitstream_buffers_.pop();

    uint8_t* target_data = reinterpret_cast<uint8_t*>(buffer->shm->memory());

    linked_ptr<EncodeJob> encode_job = submitted_encode_jobs_.front();
    submitted_encode_jobs_.pop();

    size_t data_size = 0;
    if (!vaapi_wrapper_->DownloadAndDestroyCodedBuffer(
            encode_job->coded_buffer, encode_job->input_surface->id(),
            target_data, buffer->shm->size(), &data_size)) {
        NOTIFY_ERROR(kPlatformFailureError, "Failed downloading coded buffer");
        return;
    }

    DVLOGF(3) << "Returning bitstream buffer "
              << (encode_job->keyframe ? "(keyframe)" : "")
              << " id: " << buffer->id << " size: " << data_size;

    child_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&Client::BitstreamBufferReady, client_, buffer->id, data_size,
            encode_job->keyframe, encode_job->timestamp));
}

void VaapiVideoEncodeAccelerator::Encode(const scoped_refptr<VideoFrame>& frame,
    bool force_keyframe)
{
    DVLOGF(3) << "Frame timestamp: " << frame->timestamp().InMilliseconds()
              << " force_keyframe: " << force_keyframe;
    DCHECK(child_task_runner_->BelongsToCurrentThread());

    encoder_thread_task_runner_->PostTask(
        FROM_HERE, base::Bind(&VaapiVideoEncodeAccelerator::EncodeTask, base::Unretained(this), frame, force_keyframe));
}

bool VaapiVideoEncodeAccelerator::PrepareNextJob(base::TimeDelta timestamp)
{
    if (available_va_surface_ids_.size() < kMinSurfacesToEncode)
        return false;

    DCHECK(!current_encode_job_);
    current_encode_job_.reset(new EncodeJob());

    if (!vaapi_wrapper_->CreateCodedBuffer(output_buffer_byte_size_,
            &current_encode_job_->coded_buffer)) {
        NOTIFY_ERROR(kPlatformFailureError, "Failed creating coded buffer");
        return false;
    }

    current_encode_job_->timestamp = timestamp;

    current_encode_job_->input_surface = new VASurface(
        available_va_surface_ids_.back(), coded_size_,
        vaapi_wrapper_->va_surface_format(), va_surface_release_cb_);
    available_va_surface_ids_.pop_back();

    current_encode_job_->recon_surface = new VASurface(
        available_va_surface_ids_.back(), coded_size_,
        vaapi_wrapper_->va_surface_format(), va_surface_release_cb_);
    available_va_surface_ids_.pop_back();

    // Reference surfaces are needed until the job is done, but they get
    // removed from ref_pic_list0_ when it's full at the end of job submission.
    // Keep refs to them along with the job and only release after sync.
    current_encode_job_->reference_surfaces = ref_pic_list0_;

    return true;
}

void VaapiVideoEncodeAccelerator::EncodeTask(
    const scoped_refptr<VideoFrame>& frame,
    bool force_keyframe)
{
    DCHECK(encoder_thread_task_runner_->BelongsToCurrentThread());
    DCHECK_NE(state_, kUninitialized);

    encoder_input_queue_.push(
        make_linked_ptr(new InputFrameRef(frame, force_keyframe)));
    EncodeFrameTask();
}

void VaapiVideoEncodeAccelerator::EncodeFrameTask()
{
    DCHECK(encoder_thread_task_runner_->BelongsToCurrentThread());

    if (state_ != kEncoding || encoder_input_queue_.empty())
        return;

    if (!PrepareNextJob(encoder_input_queue_.front()->frame->timestamp())) {
        DVLOGF(4) << "Not ready for next frame yet";
        return;
    }

    linked_ptr<InputFrameRef> frame_ref = encoder_input_queue_.front();
    encoder_input_queue_.pop();

    if (!UploadFrame(frame_ref->frame)) {
        NOTIFY_ERROR(kPlatformFailureError, "Failed uploading source frame to HW.");
        return;
    }

    BeginFrame(frame_ref->force_keyframe || encoding_parameters_changed_);
    encoding_parameters_changed_ = false;

    if (!SubmitFrameParameters()) {
        NOTIFY_ERROR(kPlatformFailureError, "Failed submitting frame parameters.");
        return;
    }

    if (!SubmitHeadersIfNeeded()) {
        NOTIFY_ERROR(kPlatformFailureError, "Failed submitting frame headers.");
        return;
    }

    if (!ExecuteEncode()) {
        NOTIFY_ERROR(kPlatformFailureError, "Failed submitting encode job to HW.");
        return;
    }

    EndFrame();
    TryToReturnBitstreamBuffer();
}

void VaapiVideoEncodeAccelerator::UseOutputBitstreamBuffer(
    const BitstreamBuffer& buffer)
{
    DVLOGF(4) << "id: " << buffer.id();
    DCHECK(child_task_runner_->BelongsToCurrentThread());

    if (buffer.size() < output_buffer_byte_size_) {
        NOTIFY_ERROR(kInvalidArgumentError, "Provided bitstream buffer too small");
        return;
    }

    std::unique_ptr<SharedMemoryRegion> shm(
        new SharedMemoryRegion(buffer, false));
    if (!shm->Map()) {
        NOTIFY_ERROR(kPlatformFailureError, "Failed mapping shared memory.");
        return;
    }

    std::unique_ptr<BitstreamBufferRef> buffer_ref(
        new BitstreamBufferRef(buffer.id(), std::move(shm)));

    encoder_thread_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&VaapiVideoEncodeAccelerator::UseOutputBitstreamBufferTask,
            base::Unretained(this), base::Passed(&buffer_ref)));
}

void VaapiVideoEncodeAccelerator::UseOutputBitstreamBufferTask(
    std::unique_ptr<BitstreamBufferRef> buffer_ref)
{
    DCHECK(encoder_thread_task_runner_->BelongsToCurrentThread());
    DCHECK_NE(state_, kUninitialized);

    available_bitstream_buffers_.push(make_linked_ptr(buffer_ref.release()));
    TryToReturnBitstreamBuffer();
}

void VaapiVideoEncodeAccelerator::RequestEncodingParametersChange(
    uint32_t bitrate,
    uint32_t framerate)
{
    DVLOGF(2) << "bitrate: " << bitrate << " framerate: " << framerate;
    DCHECK(child_task_runner_->BelongsToCurrentThread());

    encoder_thread_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(
            &VaapiVideoEncodeAccelerator::RequestEncodingParametersChangeTask,
            base::Unretained(this), bitrate, framerate));
}

void VaapiVideoEncodeAccelerator::UpdateRates(uint32_t bitrate,
    uint32_t framerate)
{
    if (encoder_thread_.IsRunning())
        DCHECK(encoder_thread_task_runner_->BelongsToCurrentThread());
    DCHECK_NE(bitrate, 0u);
    DCHECK_NE(framerate, 0u);
    bitrate_ = bitrate;
    framerate_ = framerate;
    cpb_size_ = bitrate_ * kCPBWindowSizeMs / 1000;
}

void VaapiVideoEncodeAccelerator::RequestEncodingParametersChangeTask(
    uint32_t bitrate,
    uint32_t framerate)
{
    DVLOGF(2) << "bitrate: " << bitrate << " framerate: " << framerate;
    DCHECK(encoder_thread_task_runner_->BelongsToCurrentThread());
    DCHECK_NE(state_, kUninitialized);

    // This is a workaround to zero being temporarily, as part of the initial
    // setup, provided by the webrtc video encode and a zero bitrate and
    // framerate not being accepted by VAAPI
    // TODO: This code is common with v4l2_video_encode_accelerator.cc, perhaps
    // it could be pulled up to RTCVideoEncoder
    if (bitrate < 1)
        bitrate = 1;
    if (framerate < 1)
        framerate = 1;

    if (bitrate_ == bitrate && framerate_ == framerate)
        return;

    UpdateRates(bitrate, framerate);

    UpdateSPS();
    GeneratePackedSPS();

    // Submit new parameters along with next frame that will be processed.
    encoding_parameters_changed_ = true;
}

void VaapiVideoEncodeAccelerator::Destroy()
{
    DCHECK(child_task_runner_->BelongsToCurrentThread());

    // Can't call client anymore after Destroy() returns.
    client_ptr_factory_.reset();
    weak_this_ptr_factory_.InvalidateWeakPtrs();

    // Early-exit encoder tasks if they are running and join the thread.
    if (encoder_thread_.IsRunning()) {
        encoder_thread_.task_runner()->PostTask(
            FROM_HERE, base::Bind(&VaapiVideoEncodeAccelerator::DestroyTask, base::Unretained(this)));
        encoder_thread_.Stop();
    }

    delete this;
}

void VaapiVideoEncodeAccelerator::DestroyTask()
{
    DVLOGF(2);
    DCHECK(encoder_thread_task_runner_->BelongsToCurrentThread());
    SetState(kError);
}

void VaapiVideoEncodeAccelerator::UpdateSPS()
{
    memset(&current_sps_, 0, sizeof(H264SPS));

    // Spec A.2 and A.3.
    switch (profile_) {
    case H264PROFILE_BASELINE:
        // Due to crbug.com/345569, we don't distinguish between constrained
        // and non-constrained baseline profiles. Since many codecs can't do
        // non-constrained, and constrained is usually what we mean (and it's a
        // subset of non-constrained), default to it.
        current_sps_.profile_idc = H264SPS::kProfileIDCBaseline;
        current_sps_.constraint_set0_flag = true;
        break;
    case H264PROFILE_MAIN:
        current_sps_.profile_idc = H264SPS::kProfileIDCMain;
        current_sps_.constraint_set1_flag = true;
        break;
    case H264PROFILE_HIGH:
        current_sps_.profile_idc = H264SPS::kProfileIDCHigh;
        break;
    default:
        NOTIMPLEMENTED();
        return;
    }

    current_sps_.level_idc = kDefaultLevelIDC;
    current_sps_.seq_parameter_set_id = 0;
    current_sps_.chroma_format_idc = kChromaFormatIDC;

    DCHECK_GE(idr_period_, 1u << 4);
    current_sps_.log2_max_frame_num_minus4 = Log2OfPowerOf2(idr_period_) - 4;
    current_sps_.pic_order_cnt_type = 0;
    current_sps_.log2_max_pic_order_cnt_lsb_minus4 = Log2OfPowerOf2(idr_period_ * 2) - 4;
    current_sps_.max_num_ref_frames = max_ref_idx_l0_size_;

    current_sps_.frame_mbs_only_flag = true;

    DCHECK_GT(mb_width_, 0u);
    DCHECK_GT(mb_height_, 0u);
    current_sps_.pic_width_in_mbs_minus1 = mb_width_ - 1;
    DCHECK(current_sps_.frame_mbs_only_flag);
    current_sps_.pic_height_in_map_units_minus1 = mb_height_ - 1;

    if (visible_size_ != coded_size_) {
        // Visible size differs from coded size, fill crop information.
        current_sps_.frame_cropping_flag = true;
        DCHECK(!current_sps_.separate_colour_plane_flag);
        // Spec table 6-1. Only 4:2:0 for now.
        DCHECK_EQ(current_sps_.chroma_format_idc, 1);
        // Spec 7.4.2.1.1. Crop is in crop units, which is 2 pixels for 4:2:0.
        const unsigned int crop_unit_x = 2;
        const unsigned int crop_unit_y = 2 * (2 - current_sps_.frame_mbs_only_flag);
        current_sps_.frame_crop_left_offset = 0;
        current_sps_.frame_crop_right_offset = (coded_size_.width() - visible_size_.width()) / crop_unit_x;
        current_sps_.frame_crop_top_offset = 0;
        current_sps_.frame_crop_bottom_offset = (coded_size_.height() - visible_size_.height()) / crop_unit_y;
    }

    current_sps_.vui_parameters_present_flag = true;
    current_sps_.timing_info_present_flag = true;
    current_sps_.num_units_in_tick = 1;
    current_sps_.time_scale = framerate_ * 2; // See equation D-2 in spec.
    current_sps_.fixed_frame_rate_flag = true;

    current_sps_.nal_hrd_parameters_present_flag = true;
    // H.264 spec ch. E.2.2.
    current_sps_.cpb_cnt_minus1 = 0;
    current_sps_.bit_rate_scale = kBitRateScale;
    current_sps_.cpb_size_scale = kCPBSizeScale;
    current_sps_.bit_rate_value_minus1[0] = (bitrate_ >> (kBitRateScale + H264SPS::kBitRateScaleConstantTerm)) - 1;
    current_sps_.cpb_size_value_minus1[0] = (cpb_size_ >> (kCPBSizeScale + H264SPS::kCPBSizeScaleConstantTerm)) - 1;
    current_sps_.cbr_flag[0] = true;
    current_sps_.initial_cpb_removal_delay_length_minus_1 = H264SPS::kDefaultInitialCPBRemovalDelayLength - 1;
    current_sps_.cpb_removal_delay_length_minus1 = H264SPS::kDefaultInitialCPBRemovalDelayLength - 1;
    current_sps_.dpb_output_delay_length_minus1 = H264SPS::kDefaultDPBOutputDelayLength - 1;
    current_sps_.time_offset_length = H264SPS::kDefaultTimeOffsetLength;
    current_sps_.low_delay_hrd_flag = false;
}

void VaapiVideoEncodeAccelerator::GeneratePackedSPS()
{
    packed_sps_.Reset();

    packed_sps_.BeginNALU(H264NALU::kSPS, 3);

    packed_sps_.AppendBits(8, current_sps_.profile_idc);
    packed_sps_.AppendBool(current_sps_.constraint_set0_flag);
    packed_sps_.AppendBool(current_sps_.constraint_set1_flag);
    packed_sps_.AppendBool(current_sps_.constraint_set2_flag);
    packed_sps_.AppendBool(current_sps_.constraint_set3_flag);
    packed_sps_.AppendBool(current_sps_.constraint_set4_flag);
    packed_sps_.AppendBool(current_sps_.constraint_set5_flag);
    packed_sps_.AppendBits(2, 0); // reserved_zero_2bits
    packed_sps_.AppendBits(8, current_sps_.level_idc);
    packed_sps_.AppendUE(current_sps_.seq_parameter_set_id);

    if (current_sps_.profile_idc == H264SPS::kProfileIDCHigh) {
        packed_sps_.AppendUE(current_sps_.chroma_format_idc);
        if (current_sps_.chroma_format_idc == 3)
            packed_sps_.AppendBool(current_sps_.separate_colour_plane_flag);
        packed_sps_.AppendUE(current_sps_.bit_depth_luma_minus8);
        packed_sps_.AppendUE(current_sps_.bit_depth_chroma_minus8);
        packed_sps_.AppendBool(current_sps_.qpprime_y_zero_transform_bypass_flag);
        packed_sps_.AppendBool(current_sps_.seq_scaling_matrix_present_flag);
        CHECK(!current_sps_.seq_scaling_matrix_present_flag);
    }

    packed_sps_.AppendUE(current_sps_.log2_max_frame_num_minus4);
    packed_sps_.AppendUE(current_sps_.pic_order_cnt_type);
    if (current_sps_.pic_order_cnt_type == 0)
        packed_sps_.AppendUE(current_sps_.log2_max_pic_order_cnt_lsb_minus4);
    else if (current_sps_.pic_order_cnt_type == 1) {
        CHECK(1);
    }

    packed_sps_.AppendUE(current_sps_.max_num_ref_frames);
    packed_sps_.AppendBool(current_sps_.gaps_in_frame_num_value_allowed_flag);
    packed_sps_.AppendUE(current_sps_.pic_width_in_mbs_minus1);
    packed_sps_.AppendUE(current_sps_.pic_height_in_map_units_minus1);

    packed_sps_.AppendBool(current_sps_.frame_mbs_only_flag);
    if (!current_sps_.frame_mbs_only_flag)
        packed_sps_.AppendBool(current_sps_.mb_adaptive_frame_field_flag);

    packed_sps_.AppendBool(current_sps_.direct_8x8_inference_flag);

    packed_sps_.AppendBool(current_sps_.frame_cropping_flag);
    if (current_sps_.frame_cropping_flag) {
        packed_sps_.AppendUE(current_sps_.frame_crop_left_offset);
        packed_sps_.AppendUE(current_sps_.frame_crop_right_offset);
        packed_sps_.AppendUE(current_sps_.frame_crop_top_offset);
        packed_sps_.AppendUE(current_sps_.frame_crop_bottom_offset);
    }

    packed_sps_.AppendBool(current_sps_.vui_parameters_present_flag);
    if (current_sps_.vui_parameters_present_flag) {
        packed_sps_.AppendBool(false); // aspect_ratio_info_present_flag
        packed_sps_.AppendBool(false); // overscan_info_present_flag
        packed_sps_.AppendBool(false); // video_signal_type_present_flag
        packed_sps_.AppendBool(false); // chroma_loc_info_present_flag

        packed_sps_.AppendBool(current_sps_.timing_info_present_flag);
        if (current_sps_.timing_info_present_flag) {
            packed_sps_.AppendBits(32, current_sps_.num_units_in_tick);
            packed_sps_.AppendBits(32, current_sps_.time_scale);
            packed_sps_.AppendBool(current_sps_.fixed_frame_rate_flag);
        }

        packed_sps_.AppendBool(current_sps_.nal_hrd_parameters_present_flag);
        if (current_sps_.nal_hrd_parameters_present_flag) {
            packed_sps_.AppendUE(current_sps_.cpb_cnt_minus1);
            packed_sps_.AppendBits(4, current_sps_.bit_rate_scale);
            packed_sps_.AppendBits(4, current_sps_.cpb_size_scale);
            CHECK_LT(base::checked_cast<size_t>(current_sps_.cpb_cnt_minus1),
                arraysize(current_sps_.bit_rate_value_minus1));
            for (int i = 0; i <= current_sps_.cpb_cnt_minus1; ++i) {
                packed_sps_.AppendUE(current_sps_.bit_rate_value_minus1[i]);
                packed_sps_.AppendUE(current_sps_.cpb_size_value_minus1[i]);
                packed_sps_.AppendBool(current_sps_.cbr_flag[i]);
            }
            packed_sps_.AppendBits(
                5, current_sps_.initial_cpb_removal_delay_length_minus_1);
            packed_sps_.AppendBits(5, current_sps_.cpb_removal_delay_length_minus1);
            packed_sps_.AppendBits(5, current_sps_.dpb_output_delay_length_minus1);
            packed_sps_.AppendBits(5, current_sps_.time_offset_length);
        }

        packed_sps_.AppendBool(false); // vcl_hrd_parameters_flag
        if (current_sps_.nal_hrd_parameters_present_flag)
            packed_sps_.AppendBool(current_sps_.low_delay_hrd_flag);

        packed_sps_.AppendBool(false); // pic_struct_present_flag
        packed_sps_.AppendBool(true); // bitstream_restriction_flag

        packed_sps_.AppendBool(false); // motion_vectors_over_pic_boundaries_flag
        packed_sps_.AppendUE(2); // max_bytes_per_pic_denom
        packed_sps_.AppendUE(1); // max_bits_per_mb_denom
        packed_sps_.AppendUE(16); // log2_max_mv_length_horizontal
        packed_sps_.AppendUE(16); // log2_max_mv_length_vertical

        // Explicitly set max_num_reorder_frames to 0 to allow the decoder to
        // output pictures early.
        packed_sps_.AppendUE(0); // max_num_reorder_frames

        // The value of max_dec_frame_buffering shall be greater than or equal to
        // max_num_ref_frames.
        const unsigned int max_dec_frame_buffering = current_sps_.max_num_ref_frames;
        packed_sps_.AppendUE(max_dec_frame_buffering);
    }

    packed_sps_.FinishNALU();
}

void VaapiVideoEncodeAccelerator::UpdatePPS()
{
    memset(&current_pps_, 0, sizeof(H264PPS));

    current_pps_.seq_parameter_set_id = current_sps_.seq_parameter_set_id;
    current_pps_.pic_parameter_set_id = 0;

    current_pps_.entropy_coding_mode_flag = current_sps_.profile_idc >= H264SPS::kProfileIDCMain;

    CHECK_GT(max_ref_idx_l0_size_, 0u);
    current_pps_.num_ref_idx_l0_default_active_minus1 = max_ref_idx_l0_size_ - 1;
    current_pps_.num_ref_idx_l1_default_active_minus1 = 0;
    DCHECK_LE(qp_, 51u);
    current_pps_.pic_init_qp_minus26 = qp_ - 26;
    current_pps_.deblocking_filter_control_present_flag = true;
    current_pps_.transform_8x8_mode_flag = (current_sps_.profile_idc == H264SPS::kProfileIDCHigh);
}

void VaapiVideoEncodeAccelerator::GeneratePackedPPS()
{
    packed_pps_.Reset();

    packed_pps_.BeginNALU(H264NALU::kPPS, 3);

    packed_pps_.AppendUE(current_pps_.pic_parameter_set_id);
    packed_pps_.AppendUE(current_pps_.seq_parameter_set_id);
    packed_pps_.AppendBool(current_pps_.entropy_coding_mode_flag);
    packed_pps_.AppendBool(
        current_pps_.bottom_field_pic_order_in_frame_present_flag);
    CHECK_EQ(current_pps_.num_slice_groups_minus1, 0);
    packed_pps_.AppendUE(current_pps_.num_slice_groups_minus1);

    packed_pps_.AppendUE(current_pps_.num_ref_idx_l0_default_active_minus1);
    packed_pps_.AppendUE(current_pps_.num_ref_idx_l1_default_active_minus1);

    packed_pps_.AppendBool(current_pps_.weighted_pred_flag);
    packed_pps_.AppendBits(2, current_pps_.weighted_bipred_idc);

    packed_pps_.AppendSE(current_pps_.pic_init_qp_minus26);
    packed_pps_.AppendSE(current_pps_.pic_init_qs_minus26);
    packed_pps_.AppendSE(current_pps_.chroma_qp_index_offset);

    packed_pps_.AppendBool(current_pps_.deblocking_filter_control_present_flag);
    packed_pps_.AppendBool(current_pps_.constrained_intra_pred_flag);
    packed_pps_.AppendBool(current_pps_.redundant_pic_cnt_present_flag);

    packed_pps_.AppendBool(current_pps_.transform_8x8_mode_flag);
    packed_pps_.AppendBool(current_pps_.pic_scaling_matrix_present_flag);
    DCHECK(!current_pps_.pic_scaling_matrix_present_flag);
    packed_pps_.AppendSE(current_pps_.second_chroma_qp_index_offset);

    packed_pps_.FinishNALU();
}

void VaapiVideoEncodeAccelerator::SetState(State state)
{
    // Only touch state on encoder thread, unless it's not running.
    if (encoder_thread_.IsRunning() && !encoder_thread_task_runner_->BelongsToCurrentThread()) {
        encoder_thread_task_runner_->PostTask(
            FROM_HERE, base::Bind(&VaapiVideoEncodeAccelerator::SetState, base::Unretained(this), state));
        return;
    }

    DVLOGF(1) << "setting state to: " << state;
    state_ = state;
}

void VaapiVideoEncodeAccelerator::NotifyError(Error error)
{
    if (!child_task_runner_->BelongsToCurrentThread()) {
        child_task_runner_->PostTask(
            FROM_HERE, base::Bind(&VaapiVideoEncodeAccelerator::NotifyError, weak_this_, error));
        return;
    }

    if (client_) {
        client_->NotifyError(error);
        client_ptr_factory_.reset();
    }
}

VaapiVideoEncodeAccelerator::EncodeJob::EncodeJob()
    : coded_buffer(VA_INVALID_ID)
    , keyframe(false)
{
}

VaapiVideoEncodeAccelerator::EncodeJob::~EncodeJob() { }

} // namespace media
